<template>
  <el-select
    :value="valueTitle"
    :disabled="disabled"
    :clearable="clearable"
    @clear="clearHandle"
  >
    <el-option
      :value="valueTitle"
      :label="valueTitle"
    >
      <el-tree
        :id="id"
        ref="selectTree"
        :accordion="accordion"
        :data="options"
        :props="props"
        :node-key="props.value"
        :default-expanded-keys="defaultExpandedKey"
        @node-click="handleNodeClick"
      ></el-tree>
    </el-option>
  </el-select>
</template>


<script>
export default {
  name: 'GoodsLevel',

  components: {},

  props: {
    id: {
      type: String,
      default: function() {
        return 'vue-level-' + +new Date() + ((Math.random() * 1000).toFixed(0) + '')
      }
    },
    /* 配置项 */
    props: {
      type: Object,
      default: () => {
        return {
          value: 'value',         // ID字段名
          label: 'label',         // 显示名称
          children: 'children'    // 子级字段名
        }
      }
    },
    /* 选项列表数据(树形结构的对象数组) */
    options: {
      type: Array,
      default: () => {
        return []
      }
    },
    /* 初始值 */
    value: {
      type: String,
      default: () => {
        return null
      }
    },
    /* 可清空选项 */
    clearable: {
      type: Boolean,
      default: () => {
        return true
      }
    },
    /* 自动收起 */
    accordion: {
      type: Boolean,
      default: () => {
        return false
      }
    },
    disabled: {
      type: Boolean,
      default: () => {
        return false
      }
    }
  },

  data() {
    return {
      valueId: this.value,    // 初始值
      valueTitle: "",
      defaultExpandedKey: []
    }
  },

  computed: {},

  watch: {
    value() {
      this.valueId = this.value
      this.initHandle()
    }
  },

  created() {
  },

  mounted() {
    this.initHandle()
  },

  destroyed() {
  },

  methods: {
    openDialog() {
      this.dialogVisible = true
    },
    closeDialog() {
      this.dialogVisible = false
    },
    // 初始化值
    initHandle() {
      // alert('this.valueId=' + this.valueId)
      let that = this
      // 这里要延迟执行，否则有BUG
      setTimeout(() => {
        if (that.valueId) {
          that.valueTitle = that.$refs.selectTree.getNode(that.valueId).data[that.props.label]     // 初始化显示
          that.$refs.selectTree.setCurrentKey(that.valueId)       // 设置默认选中
          // that.defaultExpandedKey = [that.valueId]      // 设置默认展开
        } else {
          that.valueTitle = null // 初始化显示
          that.$refs.selectTree.setCurrentKey(null) // 设置默认选中
        }
      }, 200)
      this.$nextTick(() => {
        let scrollWrap = document.querySelectorAll('.el-scrollbar .el-select-dropdown__wrap')[0]
        let scrollBar = document.querySelectorAll('.el-scrollbar .el-scrollbar__bar')
        scrollWrap.style.cssText = 'margin: 0px; max-height: none; overflow: hidden;'
        scrollBar.forEach(ele => ele.style.width = 0)
      })

    },
    // 切换选项
    handleNodeClick(node) {
      this.valueTitle = node[this.props.label]
      this.valueId = node[this.props.value]
      this.$emit('input', this.valueId)
      this.$emit('change', node)
      this.defaultExpandedKey = []
    },
    // 清除选中
    clearHandle() {
      this.valueTitle = ''
      this.valueId = null
      this.defaultExpandedKey = []
      this.clearSelected()
      this.$emit('input', null)
      this.$emit('change', {})
    },
    /* 清空选中样式 */
    clearSelected() {
      let allNode = document.querySelectorAll(`#${this.id} .el-tree-node`)
      allNode.forEach((element) => element.classList.remove('is-current'))
    }
  }
}
</script>

<style scoped>
.el-scrollbar .el-scrollbar__view .el-select-dropdown__item {
  height: auto;
  max-height: 274px;
  padding: 0;
  overflow: hidden;
  overflow-y: auto;
}

.el-select-dropdown__item.selected {
  font-weight: normal;
}

ul li >>> .el-tree .el-tree-node__content {
  height: auto;
  padding: 0 20px;
}

.el-tree-node__label {
  font-weight: normal;
}

.el-tree >>> .is-current .el-tree-node__label {
  color: #409EFF;
  font-weight: 700;
}

.el-tree >>> .is-current .el-tree-node__children .el-tree-node__label {
  color: #606266;
  font-weight: normal;
}
</style>
